Fuel injection pump



j June 20, 1961 w. o. BISCHQFF 2,988,999

FUEL INJECTIN PUMP Fi 1ed June 24, 1957 INVENTOR ll WALDEMAP o. BISCHOFF nn lBosch Arma Corporation, a corporation of New Filed .lune 24, 1957, Ser. No. 667,369 1 Claim. (Cl. 10B- 2) rThis invention relates to distributor type fuel injection pumps and has particular reference to a new and improved `pump of the type set forth which is relatively simple,

compact and economical in construction, yet efficient in operation.

The principal object of the invention is tov provide a new and improved fuel injection pump of the type set forth having simplified and economical construction means.

Gther objects and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawings. lt will be understood that changes may be made in the details of construction and arrangement of parts shown and described without departing from the spirit of the invention, as set forth in the accompanying claims, as the preferred form of the invention has been given by Way of illustration only.

Referring to the drawings:

FIG. 1 is a longitudinal sectional view of a fuel injection apparatus embodying the invention;

FlG. 2 is a sectional view taken on line 2--2 of FIG. l, looking in the direction of the arrows;

FIG. 3 is a fragmentary sectional View taken on line 3 3 of FIG. l, looking in the direction of the arrows;

and

FIG. 4 is a view 'similar to FIG. 3 but taken on line 4 4 of FlG. l, looking in the direction of the arrows.

Referring more particularly to the drawings wherein similar reference characters designate corresponding parts throughout, the apparatus shown embodying the invention includes a housing in which is positioned hydraulic head 11, which could be formed in the housing and which has a bore in which is mounted the rotary member or rotor 12 yadapted to be driven by the drive shaft 13 which is journaled in the housing.

The rotor 12 has the pumping portion 14 and the fuel distributing portion 15.

The pumping portion has a radial bore or cylinder means 16 in which is positioned the opposed plungers or piston means 17, which are adapted to be urged outwardly on their suction stroke by the spring 18, which is positioned between the plungers and, in the form shown, extends into bores in the adjacent surfaces of the plunger.

Surrounding the pumping portion 14 is the internal cam 18 having opposed lobes for effecting simultaneous reciprocation of plungers 17 and between the cam 18 and plungers 17 is provided the tappets 19 and rollers 20.

The rotor 12 has a bore 21, the outer end of which is adapted to be closed by the plug 22 which has a reduced extension 23 extending into the portion of bore 21 adjacent pumping portion 14.

The housing 10 has the fuel inlet 23a adapted to be connected to a source of fuel, which fuel passes through inlet 23a to vannular sump 24 surrounding hydraulic head 11 and is adapted to supply fuel to bore 21 by means of fill port or ports 25, which ports can be of desired number.

Hydraulic head 11 is provided with a plurality of outlets 26, each of which is adapted to be connected to a respective engine cylinder or combustion chamber for supplying fuel thereto, and the outlets Z6 are adapted to receive fuel through ports 27 from distributing groove or slot 28 on the distributing portion of the rotor which, in turn, receive fuel through annular groove or slot 29 which te States Patent communicates therewith and also communicates with fuel passage 30 from the delivery valve 31, which valve is normally retained in closed position by valve spring 32. The delivery valve is adapted to receive fuel from cavity 66 through distributing port or passage 33 `and annulus 29a. Fuel enters said cavity 66 from the discharge end of shuttle piston 35 through ports 65, one of which ports is provided for each two engine cylinders.

The hydraulic head 11 is provided with the cross or shuttle piston bore 34- in which is positioned the shuttle piston 35. Bore 34 is adapted to communicate with rotor cavity 68 through ports 36 and 36a, which connect with said bore 34 adjacent the opposite ends thereof.

Shuttle piston 35 has the bore or duct 37 extending from one end thereof to radial spill port or ports 38, which are controlled by sleeve 39 which is adapted to be longitudinally adjusted relative to ports 38 by an eccentric pin 40 on shaft 41 whereby sleeve 3-9 may be adjusted to control the spilling of fuel through ports 38.

The adjustment of sleeve 39 is controlled through the governor comprising the movable governor sleeve 46 on drive shaft 13 and which is adjusted along the rotor or drive shaft by the centrifugal weights 47, only one of which is shown, and pivoted lever 48 which has an end 49 engaging said sleeve 46 whereupon movement of the sleeve 46 lever 48 is pivoted about its Xed pivot 50, and the end 51 of lever 48 which is connected to shaft 41 through lever 52 controls the position of the sleeve 39.

For automatic control, the governor spring 53 is adjusted through adjustment of lever 54 to which one end of spring 53 is connected and which lever is adapted to be adjusted by movement of an operating lever externally of casing or housing 10 whereupon shaft 56 and lever 54 are pivoted to adjust the tension on spring 53 which has an end operatively connected to lever 48 adjacent the end thereof 51 for adjusting the governor lever in the usual manner.

In the operation of the device, fuel enters the housing 1t) through inlet port 23a into sump 24. During the suction stroke of the plungers 17, ports 25a in the rotor are in communication with fill ports Z5, which communicate with sump 24. The plungers 17 are forced outwardly by the plunger spring 18 and fuel is sucked into ports 25 and 25a into bore 68 and into the space between plungers 17.

During the rst part of the injection stroke ofthe plungers, when the plungers 17 are forced towards each other by the lobes on the cam 18, fuel ilows for a short time from the cavity or bore 68 around the plunger grooves 60 through spill port 61 inthe rotor to spill port 62 back to the sump 24.

By the time groove 60 is closed from port 61, the fill ports 25a are closed from vports 25 and pressure can be developed in the pumping chamber. The rotor is provided with one pont 64 for each two engine cylinders and these ports are equally spaced `and always in communication with the pumping chamber. Ports 36 and 36a are so arranged that first one and then the other is successively opened to one of the ports 64 during succeeding injection strokes.

The opposite ends of ports 36 and 36a are connected to bore 34 adjacent the opposite ends thereof respectively. The rotor is also provided with one port 65 for each two engine cylinders. The ports 65 are equally spaced and always in communication with cavity 66. Ports 69 and 69a are so `arranged that first one and then the other is successively opened to one of the ports 65 during succeeding injection strokes. The opposite ends of ports 69 and 69a are connected to bore 34 adjacent the opposite ends thereof respectively. The number of ports 65 and 64 would be equal in number with the same spacing, but not necessarily with the same angular relationship. Ports 65 open to annulus 66 which connect to port 33, annulus 29a to delivery valve 31.

On the flst injection stroke the piston 35 will be in the position shown in FIG. 2 with ports 36a and 69 closed. Fuel flows through port 64 and port 36 into bore 34 applying pressure to the adjacent end of piston 35. This pressure causes piston 35 to move forcing fuel out of bore 69a.

From passage 69a fuel passes through port 65 through annulus 66, port 33 to annulus 29a to the delivery valve 31 from which the fuel goes through port 30 to annulus 29 to the distributor slot 28 on the rotor and then is delivered to one of the outlets 26.

Fuel continues to flow in this direction until spill port 38 cracks open past the edge of sleeve 39. Varying the sleeve position will vary the fuel quantity spilled and thereby vary the fuel quantity delivered.

On the second injection stroke, that is, the return stroke of the shuttle piston the piston 35 is displaced by pressure fuel from port 36a into bore 34 until spill port 67 is uncovered. The high pressure fuel can now escape from po-rt 67 to sump 24 and piston 35 will not move any further in this direction because the fuel pressures against the opposite ends of the piston during spill are practically balanced and, thus, spill port 67 limits the distance of travel of the piston.

Spill port 38 working against sleeve 39 limits the piston travel in the opposite direction. It will be seen that Whatever distance the piston travels in one direction for one injection stroke, it must travel backward exactly the same amount for the next injection stroke, as the sleeve position is not changed. Therefore, the amount of fuel injected by the forward stroke of the shuttle piston is equal to the amount injected by the backward stroke and changing the sleeve position changes the fuel quantity the same amount for the both strokes.

With the present arrangement, means is provided for hydraulically balancing the shuttle piston forces and providing a sleeve control for metering on the shuttle piston. This sleeve control requires only very light forces to change its position for easier governor control and fuel metering.

It will be seen that with the present arrangement as shown, constant beginning of injection with variable ending of injection is obtained and also the hydraulic balancing of the pressure eliminates the need for positive mechanical stops.

From the foregoing it will be seen that I have provided new and improved means for obtaining all of the objects and advantages of the invention.

l claim:

In a distributor type fuel injection pump for internal combustion engines, a housing having a longitudinal bore, a rotor mounted for rot-ation in said bore, said rotor having pumping and distributing portions, said pumping portion having radial cylinder means and piston means mounted for reciprocation in said radial cylinder means,

cam means operatively associated with said piston means for effecting reciprocation of said piston means upon rotation of said rotor, said rotor having `an axial bore connecting said pumping land distributing portions, the provision of a shuttle piston bore in said housing and adapted to communicate with said axial bore upon rotation of said rotor, a shuttle piston mounted for reciprocation in said shuttle piston bore, spill passages connecting said shuttle piston bore adjacent opposite ends of said shuttle piston intermittently Wit-h an yarea of lower pressure, one of said spill passages being controlled by one end of said shuttle piston, fuel passages in said housing adapted to alternately connect the opposite ends of said shuttle piston bore to said axial bore in said rotor through peripherally spaced ports in said rotor, a plurality of outlets in said housing, a distributing port in said rotor and communicating with said yaxial bore in said rotor through said shuttle piston bore and adapted to communicate with each of said outlets successively upon rotation of said rotor whereby upon rotation of said rotor, fuel pumped by said pumping portion will be delivered through said axial bore to said distributing portion and through each of said fuel passages alternately to said shuttle piston bore and through said peripherally spaced ports in said rotor and effect movement of said shuttle piston to effect delivery of fuel from the opposite end of said shuttle piston bore through one of second fuel passages connecting the opposite ends of said shuttle piston bore and said distributing port to said distributing portion whereby it will be delivered to one of said outlets, said rst mentioned fuel passages in said housing and said peripherally spaced ports in said rotor being so arranged that when one of said rst mentioned fuel passages communicates with one end of said shuttle piston bore and `one of said spaced ports in said rotor that lanother of said second mentioned fuel passages at the opposite end of said shuttle piston bore communicates with the distributing port in said rotor, an annular sump in said housing, a fuel inlet communicating with said sump, and fuel passage means connecting said sump with said radial bore in said rotor, spill passages adapted to connect said radial cylinder means with said annular sump, the other of said spill passages in said shuttle piston bore comprising an axial bore in said shuttle piston extending from one end thereof to a radial spill port intermediate its ends, and `adjustable means for controlling the spilling of fuel through said last mentioned axial bore and spill port.

References Cited in the file of this patent UNITED STATES PATENTS 2,542,389 Broderick Feb. 20, 1951 2,641,238 Roosa June 9, 1953 2,827,852 Links Mar. 25, 1958 2,922,371 Bischoff Jan. 26, 1960 FOREIGN PATENTS 505,605 Belgium Sept. 29, 1951 1li par 

